Created by Luisa Pereira, The Well–Sequenced Synthesizer is a series of sequencers -- physical interfaces to play with musical rules. It consists of The Counterpointer, a cross between an electronic arpeggiator and a baroque music rule book, El Ordenador that carves chaos into order by applying constraints to randomly generated chord progressions and finally La Mecánica which uses a traditional music box mechanism to play back the progressions generated by El Ordenador.

The three devices utilise custom developed software with Processing, using CFGen species counterpoint app and firmware for the devices runs on Arduino. The Counterpointer is designed to take melody input and respond to it with voices that follow the rules of counterpoint. El Ordenador was inspired by the features of tonality described by Dmitri Tymoczko in "A Geometry of Music" and El Ordenador uses punched cards to give a visual representation of the patterns: where we start to perceive melodies, we also start to see lines.